So no one believes me about this, but I reset my choco (been playing with a while and decided it was just easier to restart) to follow the chart that's been posted recently. Fed apples til feather proc message ("X has begun growing new feathers!"). Got Millioncorn Yellow. As expected. Fed apples again til the feathers proc, and I KNOW it happened. Went back to check on it after the plumage change should have happened, and nothing happened. There was no message, no cutscene. My choco was still just Millioncorn Yellow. I do know the difference between the original "The plumage will change in 6 hours" and the feather proc message. And I had the feather proc message with no change.